Wear Behavior Of Composite Materials Research Articles

The Effect of B4C Amount on Wear Behaviors of Al-Graphite/B4C Hybrid Composites Produced by Mechanical Alloying

In this study, wear behavior of composite materials produced by mechanical alloying method adding different amounts of B 4 C to Al-Graphite matrix were investigated. After adding 2% (vol.) graphite to the aluminum matrix, 3 different amounts (3%, 6% and 9%) of B 4 C were added. The composite powders prepared were mechanically alloyed for 60 minutes. The milled powders were cold-pressed under 700 MPa pressure. The green compacts produced were sintered at 600 °C for 120 minutes. The sintered B 4 C reinforced aluminum composite materials (AMCs) are characterized by the scanning electron microscope (SEM+EDS), X-ray diffraction (XRD), and hardness and density measurements. Wear tests were performed on a standard pin-on-disc wear testing device with a load of 20 N at a sliding speed of 0.5 ms -1 and four different sliding distances (250-1000 m). As a result of the studies, the hardness increases as the amount of B 4 C in the composite material increases, while the density of AMC decreases. As a result of the wear tests, the highest weight loss was obtained in the non-reinforced AlGr matrix alloy, while the lowest weight loss was obtained in 9% B 4 C reinforced composite materials. However, it was observed that there was a decrease in the friction coefficient with increasing amount of reinforcement.

Topology Optimization of Composite Materials for Wear: A Route to Multifunctional Materials for Sliding Interfaces

Predicting and optimizing the wear performance of tribological systems is of great interest in many mechanical applications. Wear modeling based on elastic foundation models can be used to predict the wear behavior of composite materials. Topology optimization has previously been used to improve the wear performance of a bi‐material composite surface without direct experimental validation. In this paper, three multi‐material composite wear surfaces are presented and fabricated that are the product of topology optimization. The wear surfaces are designed for optimal wear performance including minimized run‐in wear volume lost. In this work, the designs are evaluated with high‐accuracy simulations prior to fabrication. Extensive testing is conducted including for wear volume, wear rate, surface height distribution, and profile measurements throughout the wear process. The effects of boundary conditions and the importance of taking wear sliding directionality into account in the modeling process are discussed.

Effect of Sliding Movement Mechanism on Contact Wear Behavior of Composite Materials in Simulation of Oral Environment

The aim of this study was to examine the effect of the sliding motion mechanism on contact-wear resistance of composite materials under in vitro chewing test process. In the conditions recommended by the manufacturer, composite test specimens (P60, Cleafil AP-X, Grandio, Heliomolar, Supreme, and Z250) were produced from each composite material. All test specimens were kept in pure water for at least 1-week period and Vickers hardness was determined before contact wear tests. Then contact wear tests were performed using a chewing simulation (50 N, 240.000 chewing cycles 1.2 Hz and 37 °C temperature). Each contact wear test, steatite ball with a diameter of 6 mm was used as antagonist material. Half of the specimens of each test group were loaded with a sliding movement of 0.7 mm, the other half remaining without sliding movement. The mean volume loss of all specimens after the contact wear tests was determined with use 3D profilometer. In addition to a random specimen was selected from each test group and scanning electron microscope (SEM) images were taken for analysis of wear tracks. All composite materials showed significantly more volume loss when it occurred sliding movement than without sliding movement contact wear tests. It can be suggested in this work that the larger monomer and harder surface glass structure contained in the composite material cause more volume loss when it occurred during sliding contact wear mechanism.

Friction and Wear Behaviour of Composite Materials Containing Organic Components

The paper presents the experiments performed in the laboratory and the results obtained on friction and wear behaviour of the composite materials for the manufacture of brake shoes used for driving and towed rolling stock. The tribological research of these samples made of composite material with organic components aimed to determine the influence of certain material factors and operating regime parameters on the tribological properties of the tested samples. The brake shoes made of composite materials oneusesto replace the conventional cast iron brake shoes, to reduce the noise. The future research will focus on finding composite materials with superior properties compared to the currently used ones, and lower costs.

Tribological properties of nonasbestos brake pad material by using coconut fiber

In automotive industry, the brake system is influenced by a large number of variables including geometry of components, materials of brakes, components interaction and many operating condition. Organic fiber reinforced metallic friction composites are increasingly being used in automotive brake shoes, disc and pads, linings, blocks, clutch facings, primarily because of awareness of health hazards of asbestos. Current trend in the research field of automotive industry is to utilization of different wastes as a source of raw materials for composite materials. This will provide more economical benefit and also environmental preservation by utilize the waste of natural fibre In this paper it has performed a tribological study to determine the characteristics of the friction product by using coconut natural fibred reinforced in aluminium composite. In this sense, two different laboratory formulation were prepared with 5% and 10% coconut fibre and other constitutes like binder, friction modifiers, abrasive material and solid lubrificant using powder mettallurgy. These dnew materials for brake pads are tested for tribological behaviour in a standard pin on disc tribometer. To know the wear behavior of composite materials will determine the parameters that characterize there tribological properties.

Tribological and Microstructure Behavior of Quicklime (CaO) Filled Silicon Bronze Alloy for Bearing Material

CaO filled silicon bronze (SiBr) alloy composites have been fabricated by a high temperature vacuum casting technique at five different weight percentages (0 wt%, 2.5 wt%, 5 wt%, 7.5 wt% and 10 wt% of CaO). The void contents, hardness and wear behavior of the CaO filled SiBr alloy composites were studied showing that the addition of particulates in base alloy reduces the void contents from 0.827 % to 0.504 % for 0 wt% to 7.5 wt% of CaO respectively. Similarly, the hardness of CaO filled SiBr alloy composites initially increases from 119.25 Hv to 140.8 Hv on addition of 7.5 % CaO but on further increase in filler content (10 wt%) the hardness decreases to 114.5 HV respectively. The specific wear rate of composite materials for applied load and sliding velocity factors showed surpassing behavior compared to unfilled alloy composites. To get the optimum response of wear behavior of composite materials the Taguchi L25 orthogonal array was applied and the result shows the higher S/N ratio i.e. 106.33 dB. The analysis of variance (ANOVA) result shows that the filler content plays a major effect compared to other factors. The particulate filled composites were examined through scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and atomic force microscopy (AFM) in order to understand the wear mechanism and morphology behavior of the composites.

A study on erosive wear analysis of glass fiber–epoxy–AlN hybrid composites

Aluminum nitride reinforced glass fiber epoxy resin composite was prepared by simple hand lay-up technique and its mechanical as well as erosion wear behavior were investigated. The interactive influence of various operational variables on specific wear behavior of composite materials has been studied thoroughly. It was observed that with increasing percentage of filler particles, there is a decline in tensile strength, but there is a significant improvement in hardness and erosion wear performance. Among all the factors, impact velocity is the most significant factor followed by filler percentage and impingement angle, while temperature has the least significance on erosion of the hybrid composite. Taguchi’s orthogonal arrays were used to identify the controlling factors influencing the erosion wear rate. Scanning electron microscopy studies were conducted to understand the erosion mechanism involved during the material removal process.

Characterization and prediction of abrasive wear of powder composite materials

Composite materials produced by powder metallurgy provide a solution in many engineering applications where materials with high abrasion and erosion resistance are required. The actual wear behaviour of the material is associated with many external factors (particle size, velocity, angularity, etc.) and intrinsic material properties (hardness, toughness, Young modulus, etc.). Hardness and toughness properties of such tribomaterials are highly dependent from the content of reinforcing phase, its size and from the mechanical properties of the constituent phases. In this study an attempt is made to model the erosion wear behaviour of composite materials, to calculate the wear rate and to correlate erosion rates with experimental results and material parameters. Powder composites cermets and metal–matrix composite materials reinforced with different content of hard phase were used as examples in this research. Wear mechanisms of materials were investigated. Following from the main mechanisms of erosion wear the models of plastic deformation and brittle fracture are developed for prediction of erosion of powder composite materials. It was demonstrated, that the erosion rate of hardmetal-type materials can be predicted using the results obtained by microindentation methods. The use of hardness distribution parameters is justified with materials with low binder content.

Tribological Behavior of Composite Materials - A Review

This paper presents the most recent and important research trends on the tribological behavior of different types of composite materials. For this the invention, methods, techniques, and design related to this area are discussed. The different trends of the friction and wear behavior of composite materials under different operating conditions are observed. The investigators showed that, the variation of friction coefficient and wear rate depends on normal load, sliding velocity, lubrication, and vibration etc. In this article, an attempt is made to provide an opportunity for the future researchers to identify the recent trend of these areas. It is expected that the applications of these results will contribute to the improvement of different concerned mechanical processes. This review article also includes relevant patents. Keywords: Tribology, friction coefficient, wear rate, normal load, sliding velocity, lubrication, vibration

Investigation of the influence of CuO filler and carbon fiber on wear and transfer film of nylon composites

AbstractNylon 1010 composite specimens were prepared with CuO filler and short carbon fiber (CF) as the reinforcement. Friction and wear behavior of composite materials was investigated in a ring‐block wear tester. The results show that carbon fiber was more effective in reducing friction and wear of nylon than CuO filler. Nylon composite with 20% CF and 10% CuO content filler had the lowest wear rate that could not be obtained with any proportion of the fiber or the filler alone. It was found that the transfer film on the counterpart of 20% CF–10% CuO–nylon was thin, continuous, and uniform. These differences in tribological performance have been studied according to the synergism between the carbon fiber and CuO filler. The tribochemical studies by X‐ray photoelectron spectroscopy (XPS) revealed that pure Cu, Cu2O, and Cu(OH)2 were produced due to the decomposition of CuO during sliding. Carbon fiber promoted the process of tribochemical reactions of CuO, which generated more pure Cu particle and then self‐lubricating transfer film including pure Cu was formed on the steel counterpart.© 2003 Wiley Periodicals,Inc.J Appl Polym Sci 91: 2397–2401, 2004

PM processing of Al-Al2O3 composites and their characterisation

Aluminium based composites containing 5 to 20 vol.-%Al2O3 as the reinforcing phase were synthesised by powder metallurgy. The process consisted of blending aluminium powder with Al2O3 powder followed by hot compaction and hot extrusion. The microstructural features, mechanical properties and wear characteristics of the composites were investigated with variation in volume fraction of Al2O3 phase. The results indicated a continuous increase in yield and ultimate tensile strength with a marked decrease in ductility of the composites arising from increased Al2O3 content. High temperature tensile test data revealed that the strength of the base material Al and composite materials containing 5 and 15%Al2O3 decreased with increase in temperature. However, the rate of strength reduction was higher for the extruded compact of unreinforced aluminium than the composites. Lower wear rates were observed in the composite materials than the unreinforced aluminium compacts. An increase in Al2O3 content led to a decrease in wear rate of composites under the applied load of 5-35 N and a range of sliding velocity from 0·25 to 1·5 m s-1. The reasons for improvement in strength and wear behaviour of composite materials are discussed in light of their microstructural features.

Investigation of the influence of MoS 2 filler on the tribological properties of carbon fiber reinforced nylon 1010 composites

Nylon 1010 composite specimens were prepared with MoS 2 filler and short carbon fiber as the reinforcement. The friction and wear behavior of composite materials was investigated on a ring-block wear tester where sliding occurred under dry friction condition at a speed of 0.42 ms −1 under various loads. The results showed that the addition of carbon fiber was effective in reducing friction and wear of pure nylon, but MoS 2 filler increased its wear. Wear and friction reduction were more significant while the carbon fiber was used as reinforcement along with MoS 2 filler. The tribochemical studies by XPS revealed that MoS 2 particles decomposed and MoO 3, FeS, FeSO 4 and Fe 2(SO 4) 3 were produced during sliding. It was concluded that FeS, FeSO 4 and Fe 2(SO 4) 3 compounds could increase the adhesion between the transfer film and the counterface surface. The ability of the synergistic fillers in helping the formation of thin, uniform and continuous transfer film would contribute to the increase in wear resistance of nylon composites.

Mechanical, intergranular corrosion, and wear behavior of aluminum-matrix composite materials reinforced with nickel aluminides

This article presents experimental results of important properties of aluminum-matrix (AA 2014) composite materials reinforced with different intermetallics of the Ni-Al system. For the present study, the intermetallics are prepared either by mechanical alloying (MA) or by gas atomization (GA). The reinforced composite materials were manufactured by mixing the constituents, followed by uniaxial compacting of a preform and subsequent extrusion without canning or degassing. The present study considered the materials in the extruded state and after T6 heat treatment. Assessments were made from the viewpoint of microstructure (by means of optical and scanning electron microscopy (SEM)) and thermal characteristics (by differential scanning calorimetry (DSC)), with special emphasis on studying the reactions that take place between the matrix and the reinforcement and which produce a highly copper-enriched interphase. A study was also made of the effect of this reactivity on the mechanical properties and wear behavior of the composite materials, as well as the intergranular corrosion resistance of the materials in the extruded state.

Attritional wear and abrasive surface alterations of composite resin materials in vitro

Objectives. A laboratory study was performed with 232 specimens and 72 human enamel, 24 gold, 24 ceramic and 12 composite antagonists in 22 groups to test attritional and abrasive wear behavior of composite materials compared to wear behavior of human enamel. Methods. Belleglass HP, Concept Inlay/Onlay, Targis and Targis Upgrade 99 composite resin for lab-made restorations was tested as well as Tetric Ceram and FHC Merz light as resins for direct restorations. Natural human enamel specimens served as control. All specimens were subjected to long-term thermo-mechanical loading in a computer-controlled masticator, chemical degradation and toothbrush/toothpaste abrasion. Wear of specimen in occlusal contact area (OCA), contact-free occlusal area and wear of natural enamel cusps as well as antagonists made of gold, ceramic and composite in identical form was measured after 120,000, 240,000, 640,000 and 1200,000 load cycles. A qualitative SEM analysis was performed to support quantitative data. Results. Belleglass HP and Targis Upgrade 99 restorative materials showed wear resistance comparable to human enamel when loaded with enamel cusps. Wear of Targis versus composite and gold antagonists was significantly higher ( p<0.0001). Analysis of surface alterations showed hygroscopic expansion in all composite resins during the test. Conclusions. As a consequence of this study, necessity to further improve physical properties of composites for long lasting restorations was obvious. Beside of attritional wear in OCA, attention must be given to stable filler–matrix interfaces and prevention of water sorption.

The Wear Behaviour of Composite Materials with Epoxy Matrix Filled with Hard Powder

The wear behaviour of composite materials, sliding under dry conditions against smooth steel counterface, has been investigated. The composite materials consisted of glass woven fabric reinforcing three different systems of matrix: epoxy resin, epoxy resin filled with powders of silica and epoxy resin filled with powders of tungsten carbide. The powders were mixed in a volumetric fraction of 6% with the epoxy resin. Three laminates were manufactured by hand lay up technology. The sliding tests have been conducted on the specimens, cut from the three laminates, with a pin on disk apparatus. The results put in evidence different wear behaviours of the composite materials observed at different values of sliding speed and pressure. The presence of different wear mechanisms has been appreciated by SEM-micrographic examinations.